Isothermal process for converting naphtha to light paraffins

Abstract

A process for converting naphtha is disclosed. The process comprises contacting a naphtha stream and a hydrogen stream with a catalyst in a reactant passage of a reactor to produce a light paraffinic stream. The reactant passage is cooled by indirect heat exchange with a heat transferred media in a cooling passage adjacent to the reactant passage. The light paraffinic stream is separated into an ethane stream and a propane stream.

1 . A process for converting naphtha comprising:
 contacting a naphtha stream and a hydrogen stream with a catalyst in a reactant passage of a reactor to produce a light paraffinic stream;   cooling said reactant passage by indirect heat exchange with a heat transferred media in a cooling passage adjacent to said reactant passage; and   separating the light paraffin stream into an ethane stream and a propane stream.   
     
     
         2 . The process of  claim 1  further comprising a first zone in the cooling passages comprising a first heat exchange inlet and a first heat exchange outlet and a second zone in the cooling passages comprising a second heat exchange inlet and a second heat exchange outlet. 
     
     
         3 . The process of  claim 2 , wherein the first zone is located in a top quarter of the reactor height. 
     
     
         4 . The process of  claim 2 , wherein the first zone is at a lower temperature than the second zone. 
     
     
         5 . The process of  claim 1 , wherein the reactant passage comprises a tube bundle comprising a plurality of tubes filled with the catalyst. 
     
     
         6 . The process of  claim 4 , wherein the reactor comprises a reactor shell enclosing the tube bundle and wherein the cooling passage is in shell side of the reactor. 
     
     
         7 . The process of  claim 1 , wherein the reactor comprises an inlet for the reactant and an outlet for the reactor effluent, and wherein maximum temperature in the reactor is within 10° C. of a temperature at the outlet for the reactant. 
     
     
         8 . The process of  claim 1 , wherein the heat transfer media is in a molten state. 
     
     
         9 . The process of  claim 1  further comprising:
 heating the heat transfer media to provide a molten heat transfer media; 
 passing the molten heat transfer media to the cooling passage through a media inlet to contact and cool the reactant passage; 
 taking a contacted molten heat transfer media from the cooling passage through a media outlet; and 
 cooling said contacted molten heat transfer media in a media cooler to provide a cooled molten heat transfer media. 
 
     
     
         10 . The process of  claim 1 , wherein the heat transfer media comprises one or more salts selected from sodium nitrite, sodium nitrate, and potassium nitrate. 
     
     
         11 . The process of  claim 1 , wherein the heat transfer media has a melting temperature in the range of about 100° C. to about 450° C. 
     
     
         12 . The process of  claim 1 , wherein the naphtha stream is passed to a top of the reactant passage and the cooling media is passed to a side of the reactant passage. 
     
     
         13 . A process for converting naphtha comprising:
 contacting a naphtha stream and a hydrogen stream with catalyst in a reactant passage of a reactor having an inlet and an outlet to produce a light paraffin stream;   cooling said reactant passage by indirect heat exchange with a heat transfer media in a cooling passage adjacent to said reactant passage; and   separating the light paraffin stream into an ethane stream and a propane stream,   wherein maximum temperature in the reactor is within 10° C. of a temperature at the outlet for the reactant.   
     
     
         14 . The process of  claim 13  further comprising:
 heating the heat transfer media to provide a molten heat media; and 
 passing the molten heat media to an inlet of the cooling passage. 
 
     
     
         15 . The process of  claim 14  further comprising a cooler in communication with an outlet of the cooling passage to cool a molten heat media. 
     
     
         16 . The process of  claim 14 , wherein the heat transfer media comprises one or more salts selected from sodium nitrite, sodium nitrate, and potassium nitrate. 
     
     
         17 . The process of  claim 14 , wherein the naphtha stream is passed to a top of the reactant passage and the cooling media is passed to a side of the reactant passage. 
     
     
         18 . A process for converting naphtha comprising:
 contacting a naphtha stream and a hydrogen stream with catalyst in a reactant passage comprising a tube bundle to produce a light paraffin stream;   cooling said reactant passage by indirect heat exchange with a heat transfer media in a cooling passage adjacent to said reactant passage and enclosing the tube bundle; and   separating the light paraffin stream into an ethane stream and a propane stream.   
     
     
         19 . The process of  claim 18 , wherein maximum temperature in the reactor is within 10° C. of a temperature at the outlet for the reactant. 
     
     
         20 . The process of  claim 18 , wherein the heat transfer media is a molten heat transfer media.